PARASITIC FEAST: Outbreaks of swimmer’s itch common, physician says

Depending on where in the world you live, you may know it as lake itch, duck itch, or even rice paddy itch. Physicians call it cercarial dermatitis. Here in southern Utah, we call it swimmer’s itch.

Swimmer’s itch is a rash that resembles bug bites. It is caused by flatworm parasites found in lakes or bodies of slow-moving water. The parasites live their life cycles moving from snails to vertebrate animals — generally waterfowl — and back again. Occasionally when the parasites are looking for a duck or goose to attach themselves to they will penetrate human skin instead. When this happens, the parasite dies immediately, causing an immune system reaction in the human.

Swimmer’s itch is a problem in some areas on almost an annual basis. This year is no exception.

“The low water and these warm summer months seem to cause outbreaks,” confirmed dermatologist Dr. Ben Adams. “The organism that causes swimmer’s itch is usually found in shallow water, muddy water, and near aquatic vegetation.”

Not all lakes and streams host the parasite; the organism needs just the right combination of snails, waterfowl, and warm shallow water to flourish. In southern Utah the most common area for people to come in contact with the swimmer’s itch flatworm is Sand Hollow Reservoir.

The rash associated with swimmer’s itch can look like several other conditions, including bug bites and chicken pox. Swimmer’s itch does not usually occur under the areas covered by a swimsuit.

“A diagnosis of swimmer’s itch is generally made by looking at the history of exposure,” said Dr. Adams. “If you’re in water that’s known to have swimmer’s itch and develop spots over the next twelve hours that look like pimples or small blisters, you probably have swimmer’s itch.

“Swimmer’s itch is not contagious,” he added. “It is pretty self-limited, and will go away on its own within a week or two. It won’t spread, even if you scratch it. The biggest worry is that if you scratch too much you can get a secondary infection.”

Although it is not a serious condition, swimmer’s itch can be pretty miserable. Tips for prevention include:

• Staying out of shallow water

• Staying away from lakes that have a known swimmer’s itch problem

• Using waterproof sunscreen

• Toweling off immediately after coming in from the water

Treatment for the condition is mostly about soothing the itch.

“Over-the-counter hydrocortisone, antihistamines, cool compresses, Epsom salts, calamine or Benadryl lotion, and oatmeal baths can help treat the itching symptoms,” said Dr. Adams. “If swimmer’s itch gets really severe, does not go away after a week or two, or if you suspect a secondary infection, see a healthcare provider.”

This Live Well column represents collaboration between healthcare professionals, The Foundation of Dixie Regional Medical Center (a not-for-profit hospital) and The Spectrum. Contact 251-2108 for more information.